Groundbreaking 3D mapping of previously inaccessible areas of the Antarctic has found that the sea ice fringing the vast continent is thicker than previous thought.
Two expeditions to Antarctica by scientists from the UK, USA and Australia analyzed an area of ice spanning 500,000 metres squared, using a robot known as SeaBed.
The survey discovered ice thickness average between 1.4 m and 5.5 m, with a maximum ice thickness of 16 m. Scientists also discovered that 76% of the mapped ice was ‘deformed’, meaning that huge slabs of ice have crashed into each other to create larger, denser bodies of ice.
The team behind the research, published in Nature Geo-science, have hailed it as an important breakthrough in better understanding the vast icy wilderness. The findings will provide a starting point to further work to discover how ice thickness, as well as extent, is changing.
Previously, measurements of Antarctic ice thickness were hindered by technological constraints. Ice breaking ships could only go so far into ice to measure depth, while no-one had drilled much more than 5.5 m down into the ice to extract a core for analysis.
SeaBed, an autonomous underwater vehicle (or AUV), was used by the research team to analyze ice thickness at an underwater depth of 20 to 30 meters. Driven in a “lawnmower” pattern, the two-meter long robot used upward-looking sonar to measure and map the underside of sea ice floes. Oceanography robots are usually focused on the sea floor.
The mapping took place during two expeditions, in 2010 and 2012, that took researchers to the coastal areas of the Weddell, Bellingshausen and Wilkes Land regions of Antarctica. The teams came from the British Antarctic Survey, the Institute of Marine and Antarctic Studies in Tasmania and the Woods Hole Oceanographic Institution in the US.
Dr. Guy Williams, from IMAS, said the research is an important step in gauging changes to Antarctic ice.
“Sea ice is an important indicator of the polar climate but measuring its thickness has been tricky,” said Williams, the report’s co-author. “Along with the satellite data, it was a bit like taking an X-ray of the ice, although we haven’t X-rayed much of it, just a postage stamp.
